Cat tree tower



FIG. 1 is a front elevational view of a cat tree tower, showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a top, front and right side perspective view thereof.

The broken lines in the drawings illustrate the portions of the cat tree tower, which form no part of the claimed design. 

CLAIM The ornamental design for a cat tree tower, substantially as shown and described. 